Thermal insulation vacuum panels are known in the art. One such panel is disclosed in U.S. Pat. No. 2,768,046. That panel comprises a metal shell or envelope formed from a pan-shaped metal sheet and a generally flat metal sheet. The sheets are welded to one another at their abutting outer edges. The edges define a flange which extends about the outer periphery of the panel. The space between the two sheets is filled with glass fiber insulation and the enclosed spaced is evacuated to a very low pressure.
The patentee teaches incorporating a plurality of his panels into a refrigerator cabinet. He notes in column 1, lines 45-49 of the '046 patent that heat transfer can occur from one wall or sheet of the panel to the other at the abutting edges of the sheets. In an attempt to minimize the effect of such edge leakage, the patentee encases the edges of each panel between opposing wall sections and provides glass fiber insulation between the wall sections adjacent to the panel edges. As to the door specifically, the patentee teaches forming the wall sections such that a portion of increased thickness is provided along the perimeter of the door. This substantial increase in the thickness of the walls of the cabinet reduces the useable space within the cabinet and, hence, is undesirable. Furthermore, in other contexts where vacuum panels might be used, encasing a vacuum panel between spaced apart walls and providing batts of glass fiber material adjacent the panel edges will not always be practical or desirable.
Vacuum insulation panels having uniform edge dimensions can be difficult to manufacture. Dimensional error may occur during one or more of the following manufacturing operations: cutting or otherwise forming the first and second sections of the metal envelope, positioning the two sections adjacent to one another and welding their abutting edges together, and evacuating the envelope. Because most vacuum panels do not have uniform outer dimensions, it is difficult to construct a wall, ceiling or other structure by positioning vacuum panels adjacent to one another.
Accordingly, there is a need in the art for a thermal insulation vacuum panel which has improved thermal performance, particularly at its outer edges, can be manufactured so as to have uniform edge dimensions to allow use of such panels in a modular fashion to construct walls, ceilings and other structures, can be easily manufactured in a number of panel sizes, and permits it to be easily and safely handled and transported. Further, there is a need for new structural designs which employ modular insulation panels.